1. Field of the Invention
The present invention relates generally to power supplies and, more particularly, to power supplies with feedback loops.
2. Description of the Related Art
Power supplies typically provide a voltage at a preset or programmed output level to a load impedance. Since the physical output impedance of a power supply is never zero, absent a compensating scheme, the output voltage of the power supply would experience a deviation from the desired value dependent on the impedance of the load. Feedback loops are typically employed to compensate for load-dependence of the output voltage such that a constant output voltage is maintained as the current sourced by the power supply changes.
Recently, power supplies and voltage regulators that use digital feedback loops instead of analog feedback loops have been described. See, for example, Merrill, “Digital Feedback Power Supply” (U.S. Pat. No. 5,969,514); Goodfellow, “Digitally Controlled Voltage Regulator” (U.S. Pat. No. 7,023,672). The digital feedback loop is distinguishable from the analog feedback loop in that in the former, the analog signal representing the output voltage is converted into digital data by an analog-to-digital-converter (ADC) and at least some of the signal processing associated with the feedback loop is done in the digital domain.
Although prior art power supplies with an analog or a digital feedback loop provide a constant voltage source for some applications, the flexibility is still limited. In some environments, digital output regulation has never been implemented.